A U.S. Manufacturer of Repeater and Interoperability Controllers and Accessories

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Bob's Blog #12: Long Tone Zero (LiTZ)

S-COM’s 6K, 7K, and 7330 support a feature known as Long Tone Zero, or LiTZ. If you’re not familiar with it, read on!

LiTZ is a system for requesting aid during an emergency. It’s simple: Transmit a DTMF “0” character for at least 3 seconds and then announce your emergency. Nearly all modern mobiles and handhelds have DTMF keypads, so no additional hardware is needed by the user.

Bob's Blog #2: 7330 Internal Audio Levels

(Revised 07-03-2018)

The 7330 User Manual’s Appendix B (Installation) recommends adjusting the three receive audio pots for 1 V peak-to-peak as measured by an oscilloscope at test points TP9 (RX1), TP10 (RX2), and TP11 (RX3).

The 1 V p-p level is maintained throughout the audio section of the controller. This blog explains why that level was chosen.

Bob's Blog #11: Coin Cells

Lithium coin cells (batteries) are very popular for timekeeping and memory backup applications. Ever wonder why?


Fast facts

The output voltage is 3 V, roughly double that of other common battery types. Designers can use one lithium coin cell instead of two cells of other chemistries.

Bob's Blog #10: Memory

Let’s take a stroll down Random Access Memory Lane to see how controller memory evolved over the years.


Bob's Blog #9 - Timekeeping

Let’s take a then-and-now look at how generations of S-COM controllers kept time.

The term for what we’re talking about is Real-Time Clock, or RTC. It refers to timekeeping in human terms (time and date) rather than the cyclical clock signal used to synchronize logic. RTC can be implemented in software or with an integrated circuit that tracks time and date independently of microprocessor intervention.

Bob's Blog #8 - Why an External Controller?

Today, most repeaters are available with internal controllers. This presents the owner with a choice: Do I retain the internal controller, or add an external one at extra cost? Let’s look at the differences and some reasons for upgrading to a larger model.

Bob's Blog #7 - Triple Repeater Control

If you own a 7330, you know that its flexibility in port programming is unmatched in repeater controllers.

How did it get that way? Let’s go back some years...

The 7K is in its prime and is our flagship model. It’s designed to support one repeater, one link transceiver, and one control receiver. It’s still doing its job well, but we’re getting more frequent requests to have it control two or three repeaters instead.

Interface 7330 to Yaesu System Fusion Repeater

The Yaesu DR-1X and DR-2X are multimode repeaters that support analog and digital voice.

The 7330 can add functionality to the DR-1X and DR-2X in several ways:

Yaesu DR-2X and the S-COM 7330

[Update 11/18/2017] At S-COM, we've been testing the DR-2X with the S-COM 7330 repeater controllers. The DR-2X that I have has the external controller modification and the latest firmware.

Here's the two configurations that I have tested and work well:

Bob's Blog #6: Cabinets

So why are we dedicating a blog to a boring topic like cabinets? Are they made of Valyrian steel?

Nope, aluminum. But we hope you’ll find the details interesting anyway.

Our repeater controller cabinets are made of 5052-H32 aluminum alloy sheet. It’s strong, light, formable, and commonly used for aircraft, marine, and commercial-grade parts.

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